Study on the wrinkling of liner with elliptical defects in lined pipes under axial compression

Transporting corrosive hydrocarbons using the lined pipe is an economical method and has been widely applied in onshore and offshore pipeline systems. However, initial ovality is inevitable in the liner during manufacturing, which can affect the mechanical properties and service life of lined pipes. In this paper, a new lined pipe model considering the initial elliptic defects of the liner is established, and the effect of initial elliptic defects on the liner wrinkling is analyzed by the finite element method. The wrinkling behavior of lined pipes with perfect and elliptic liners under axial compression is studied and compared. Results show that the contact stress on the lined pipe is uneven, and the extent of nonuniformity increases as the ellipticity increases. A large ellipticity can weaken the lined pipe's load-carrying capability. Results also indicate that the liner wrinkling in the lined pipe is sensitive to the initial elliptic defects.